Slow-release ammonium bicarbonate fungicide compositions

ABSTRACT

This invention provides a fungicide composition which is capable of in situ generation of ammonium bicarbonate when applied to plant foliage in the form of an aqueous dispersion. The constituents include (1) an ingredient such as urea which slow-releases ammonia under aqueous alkaline pH conditions; and (2) an alkali metal bicarbonate ingredient which imparts alkalinity to the aqueous dispersion, and provides bicarbonate ions for combination with the released ammonium ions. A spreader-sticker ingredient is included to maintain the ingredients in contact with plant foliage over an extended period after application.

BACKGROUND OF THE INVENTION

The control of phytopathogenic fungi is of great economic importancesince fungal growth on plants or on parts of plants inhibits productionof foliage, fruit or seed, and diminishes the overall quality of acultivated crop.

Because of the vast economic ramifications of fungal propagation inagricultural and horticultural cultivations, a broad spectrum offungicidal and fungistatic products have been developed for general andspecific applications.

Of particular interest with respect to the present invention embodimentsare fungicide compositions which contain an inorganic bicarbonate orcarbonate compound. It is known that bicarbonate and carbonate compoundsexhibit fungicidal properties for agricultural purposes.

Phytopathology, 48, 169 (1931) by R. H. Marloth describes studiesinvolving the physiology of fungi. The reference reports studies whichdemonstrate that sodium and potassium bicarbonate and carbonate saltsare toxic to fungi such as Penicillum italicum and Penicillum digitalum.

U.S. Pat. No. 1,560,558 discloses the use of salts such as lithiumcarbonate, sodium carbonate, sodium bicarbonate, potassium bicarbonate,potassium carbonate and ammonium bicarbonate as fungicide ingredients.

U.S. Pat. No. 4,599,233 describes a fungicide composition which consistsof sodium bicarbonate in combination with a surface active foodemulsifier such as sorbitan monostearate.

Japanese patent 53096319 describes the application of potassiumbicarbonate as an active biocide for the control of fungal diseasescommon to tomato and cucumber plants.

Japanese patent 56043207 describes a biocidal composition containingsodium bicarbonate and a polyglycerol fatty acid ester. The biocidecontrols Penicillum digitatum on oranges, Sphaerotheca fuligenea oncucumbers, Piricularia oryzae on rice, and mosaic virus on tomatoes.

Japanese patent 60097909 describes a soil fungicide prepared by admixingslaked lime with sodium bicarbonate, potassium bicarbonate, boric acidand phenolphthalein.

Japanese patent 57062208 describes horticultural fungicides in which theaddition of sodium bicarbonate to polyoxin or thiophanatemethylincreases the fungicidal activity of the organic biocide againstbotrytis cinerea on cucumbers.

Japanese patent 58023609 describes an agricultural fungicide composed ofa mixture of sodium bicarbonate or potassium bicarbonate with cuprichydroxide, basic copper carbonate or basic copper sulfate. Thecombination of ingredients exhibits a synergistic fungicidal effectagainst cucumber early blight, tomato wilt, rice sheath blight, riceblast and citrus canker.

While the fungicidal activities of alkali metal bicarbonates arewell-established, there is less certainty concerning the fungicidalactivity of the related ammonium bicarbonate. In vitro studies indicatethat ammonium bicarbonate often is more effective than sodium orpotassium bicarbonate for control of fungus growth. Incontradistinction, in vivo application of ammonium bicarbonate generallyis not effective for control of foliar fungi. Sodium and potassiumbicarbonate but not ammonium bicarbonate are effective for controllingpowdery mildew on roses. However, ammonium bicarbonate is efficaciousfor control of soil fungi such as Sclerotinia sclerotiorum infection ofpeanut crops.

It appears that ammonium bicarbonate is less effective in plant foliarapplications for fungus control because ammonium bicarbonate is lessstable than alkali metal bicarbonate under ambient temperature andmoisture conditions. The ammonium bicarbonate does not remain intact asan active biocidal entity for a sustained duration and in a sufficientcontact concentration to achieve fungus control.

There is a continuing interest in the development of new and moreeffective fungicides which possess preventive, curative and systemicactivity for the protection of cultivated plants, with a minimum ofphytotoxic side effects.

Accordingly, it is an object of this invention to provide a dry blendbiocide composition which releases at least two bicarbonate ingredientsexhibiting fungicidal properties when applied to agricultural andhorticultural plants as a powder, an aqueous dispersion, or a solution.

It is another object of this invention to provide a fungicidecomposition which is an aqueous formulation of ingredients adapted forsustained in situ generation of ammonium bicarbonate when applied toplant foliage.

Other objects and advantages of the present invention shall becomeapparent from the accompanying description and examples.

DESCRIPTION OF THE INVENTION

One or more objects of the present invention are accomplished by theprovision of a fungicide composition consisting of a dry blendformulation adapted for in situ generation of ammonium bicarbonate whichcomprises (1) between about 5-80 weight percent of an ingredientselected from water-soluble organic amides which slow-release ammoniaunder aqueous alkaline pH conditions at ambient temperatures; (2)between about 10-80 weight percent of an ingredient selected from alkalimetal bicarbonates; (3) between about 0-30 weight percent of aningredient selected from alkali metal and ammonium carbonates; and (4)between about 0.5-20 weight percent of a spreader-sticker ingredient;based on the composition weight.

An invention dry blend fungicide composition can be in the form ofdusting powders, which optionally can include a solid diluent such asbentonite, calcium carbonate, magnesia, gypsum, kieselguhr, diatomaceousearth, and the like. Plant foliage can be treated with a dusting powder,and ambient weather cycles and atmospheric conditions provide sufficientmoisture to convert the applied dusting powder to an adherent coating onthe plant foliage. A dusting powder preferably has an average particlesize diameter between about 1-100 microns, and has a content ofsubmicron particles.

A dry blend fungicide composition also can be diluted with water to formaqueous fungicidal solutions with controlled rheological properties. Anaqueous fungicidal solution typically contains less than about 5 weightpercent of active ingredients, based on the solution weight. For mostapplications the content of bicarbonate ingredient is maintained at aconcentration below about one weight percent, as a means of minimizingphytotoxic effects on treated plants which are sensitive to alkaline pHconditions.

In another embodiment this invention provides an aqueous fungicidalformulation adapted for in situ generation of ammonium bicarbonate undercultivated plant application conditions, which contains ingredientscomprising (1) between about 0.1-5 weight percent of water-solubleorganic amide which slow-releases ammonia under aqueous alkaline pHconditions at ambient temperature; (2) between about 0.2-5 weightpercent of alkali metal bicarbonate; (3) between about 0-2 weightpercent of alkali metal or ammonium carbonate; and (4) between about0.02-1.5 weight percent of a spreader-sticker ingredient; based on theformulation weight.

A preferred aqueous formulation has a carbonate salt content betweenabout 0.1-1 weight percent.

In another embodiment this invention provides a method of controllingfungal disease in cultivated plants which comprises applying a presentinvention fungicide composition to the plant foliage to prevent oreradicate fungal infections.

The term "water-soluble" as employed herein refers to an organic amidewhich has a solubility of at least about 0.5 gram per 100 grams of waterat 25° C.

Illustrative of water-soluble organic amides which slow-release ammoniain accordance with the present invention are urea; urea-formaldehydeadducts such as monomethyloeurea and dimethyloeurea; urea hydrochloride;urea nitrate; urea phosphate; alkali metal carbamate; biuret; triuret;cyanuric acid; and the like.

A urea ingredient also can be included in the form of a crystalline ureaclathrate complex, which contains an occluded long chain compound whichcan exhibit spreader-sticker properties on foliage surfaces. In anaqueous medium the clathrate complex dissociates, and the urea and longchain compound function as separate molecules. The occluded long chaincompound can be an anionic, cationic or nonionic surfactant, or aparaffinic type spray oil used in crop applications.

Illustrative of a crystalline clathrate is a combination of urea with anethoxylated C₁₂ -C₁₅ alcohol containing an average of 7 moles ofethylene oxide. The clathrate is prepared by heating a mixture of onepart alcohol and 5 parts urea to 150° C. to form a melt, and thencooling the liquid mixture to yield a crystalline clathrate complex ofthe two compounds.

The bicarbonate salt ingredient of an invention fungicide composition issodium bicarbonate or potassium bicarbonate or a mixture thereof.

Optionally, the alkali metal bicarbonate ingredient of an inventionfungicide composition can be generated in situ in an aqueous medium.Thus, when urea is employed as the slow-release source of ammonia, ithydrolyzes to generate ammonia and bicarbonate ions. The net productresult is the formation of ammonium bicarbonate in situ and the releaseof ammonia.

NH₂ CONH₂ +H₂ O→NH₂ CO₂ NH₄

NH₂ CO₂ NH₄ +H₂ O→NH₄ HCO₃ +NH₃

The alkali metal bicarbonate formation in situ can be accomplished byemploying a urea acid salt such as urea hydrochloride, in combinationwith an alkali metal carbonate such as potassium carbonate. Thehydrochloride and carbonate react to form a bicarbonate salt in situ.

The optional carbonate salt ingredient of an invention fungicidecomposition is selected from sodium carbonate, potassium carbonate,ammonium carbonate, lithium carbonate, and any mixture thereof. Thecarbonate salt serves to catalyze the hydrolysis of the ammoniareleasing amide. An additional or alternative means of increasing theammonia release rate is by utilizing an enzyme such as urease tocatalyze the amide hydrolysis.

The spreader-sticker ingredient can consist of one or more componentswhich function as a surfactant or a thickening agent.

Surfactants suitable for aqueous fungicide formulations are listed inpublications such as U.S. Pat. No. 3,541,213. One type of surfactant isan alkali metal or ammonium salt of a C₈ -C₂₂ aliphatic-containingcarboxylate, sulfonate, sulfate or phosphate.

Illustrative of other surfactant types are dioctyl sodiumsulfosuccinate, cetyltrimethyl-ammonium bromide; sodium lauryl sulfate;sodium dodecylbenzenesulfonate; ammonium lignosulfonate; condensationproducts of ethylene oxide with fatty alcohols, amines or alkylphenols;partial esters of fatty acids and hexitol anhydrides; and the like.

Thickening agents are illustrated by water-soluble polymers whichexhibit pseudoplastic properties in an aqueous medium such as gumarabic, gum karaya, gum tragacanth, guar gum, locust bean gum, xanthangum, carrageenan, alginate salt, casein, dextran, pectin, agar,2-hydroxyethyl starch, 2-aminoethyl starch, 2-hydroxyethyl cellulose,methyl cellulose, carboxymethyl cellulose salt, cellulose sulfate salt,polyacrylamide, methyl vinyl ether/maleic anhydride copolymer,styrene/maleic anhydride copolymer, ethylene/maleic anhydride copolymer,the corresponding alkali metal salts of the maleic anhydride copolymers,alkali metal salts of poly(meth)acrylate, and the like.

Many of the water-soluble polymers are large volume commercial products.Sodium carboxymethyl cellulose (CMC) is available in powder or granularform having a particle size of 50-200 microns. CMC is available in adegree of substitution (DS) range of 0.38-1.4.

Oils which can be employed as a spreader-sticker ingredient in aninvention fungicide composition include Orchex 796, Volck Oil #70,Sunoco Oil No. 7E, castor oil, corn oil, and similar nonphytotoxic sprayoils of vegetable, animal or mineral origin commonly used inagricultural applications.

The ingredients in an invention fungicide composition can be selected toinclude nitrogen, phosphorus and potassium elements in a ratio thatqualifies the composition to function as a fertilizer in addition to itsfunction as a fungicide, when applied to cultivated crops. A typicalratio is 10-15-10. Besides nitrogen, phosphorus and potassium, aninvention fungicidal fertilizer composition can contain trace elements,and other essential elements as exemplified by sulfur as contained in acompound such as sodium bisulfite or thiourea.

For purposes of this additional embodiment, the present inventionprovides a fungicidal fertilizer composition consisting of a dry blendformulation adapted for in situ generation of ammonium bicarbonate whichcomprises (1) between about 5-80 weight percent of an ingredientselected from water-soluble organic amides which slow-release ammoniaunder aqueous alkaline pH conditions at ambient temperatures; (2)between about 10-80 weight percent of an ingredient selected from alkalimetal bicarbonates; (3) between about 0-30 weight percent of aningredient selected from alkali metal and ammonium carbonates; (4)between about 0.5-20 weight percent of a spreader-sticker ingredient;and (5) between about 10-60 weight percent of an ingredient selectedfrom phosphorus-containing 5 compounds; based on the composition weight;wherein the composition ingredients have a formulated ratio of nitrogen,phosphorus and potassium elements.

In a further embodiment this invention provides an aqueous fungicidalfertilizer formulation adapted for in situ generation of ammoniumbicarbonate under cultivated plant application conditions, whichcontains ingredients comprising (1) between about 0.2-5 weight percentof water-soluble organic amide which slow-releases ammonium underaqueous alkaline pH conditions at ambient temperature; (2) between about0.5-5 weight percent of alkali metal bicarbonate; (3) between about 0-2weight percent of alkali metal or ammonium carbonate; (4) between about0.02-1.5 weight percent of a spreader-sticker ingredient; and (5)between about 0.5-4 weight percent of an ingredient selected fromphosphorus-containing compounds; based on the formulation weight;wherein the composition ingredients have a formulated ratio of nitrogen,phosphorus and potassium elements.

An invention fungicide composition can include one or more otherbiologically active ingredients, such as those which exhibit herbicidal,insecticidal or plant growth regulating activity.

A fungicide composition of the present invention has a novel combinationof properties for the practice of fungus control in agricultural andhorticultural applications.

The multiple bicarbonate ingredients exhibit fungicidal properties, andthe efficiency of any additionally included organic pesticide ingredientusually is enhanced by the presence of the bicarbonate ingredients. Alesser quantity of optional pesticide ingredient can be employed toachieve a desired degree of pest control.

A present invention fungicide composition can be formulated to exhibitno phytotoxicity, or to minimize the toxic effects of salt stress onplants by the bicarbonate ingredients.

A present invention fungicide composition provides particular advantagefor the control of infectious phytopathogenic fungi which thrive underacidic soil conditions.

All of the invention fungicide composition ingredients are biocompatiblewhen the composition is applied in an agricultural environment. Theorganic amide, bicarbonate and spreader-sticker ingredients are allharmless to animals and humans.

A significant feature of a present invention dry blend fungicidecomposition is the presence of a spreader-sticker ingredient when thefungicide composition is applied to plant foliage as a water-dilutedsolution. An applied aqueous solution forms an adherent coating ofingredients on plant foliage or fruit. A surfactant type ingredient aidsin spreading and sticking the fungicide composition ingredients to thefoliage or fruit to which it is applied. A hydrophilic polymer typeingredient increases the amount of aqueous fungicide composition whichadheres to the plant surfaces because of its static high apparentviscosity. During a spraying procedure, the hydrophilic polymeringredient contributes a low pseudoplastic viscosity to the spraysolution, which facilitates the spraying action. After spraying, theapplied coating resists drifting under wind conditions, and exhibitshumectant properties in addition to enhanced fungicidal activity.

Another important advantage of a preferred invention fungicidecomposition derives from the water-solubility of the main ingredients. Acoating of an invention fungicide composition on plant foliage or fruitcan be removed readily by water-washing.

A unique feature of a present invention fungicide composition is the insitu generation of ammonium bicarbonate when the formulation has beenapplied to pre-harvest or post-harvest crops. Under conditions ofambient temperature and moisture, the organic amide releases ammoniumions over a sustained period of about 5-20 days after application of thefungicide composition. The slow-released ammonia and/or ammoniumbicarbonate enhance the direct fungicidal activity of the otherbicarbonates in the composition. The prolonged presence of ammoniumbicarbonate on plant foliage or in soil provides an exceptional fungalcontrol activity, as compared to an equivalent quantity or alkali metalbicarbonate in the absence of slow-release ammonium bicarbonate.

The following examples are further illustrative of the presentinvention. The components and specific ingredients are presented asbeing typical, and various modifications can be derived in view of theforegoing disclosure within the scope of the invention.

EXAMPLE I

This Example illustrates the preparation of in situ generating ammoniumbicarbonate fungicide compositions in accordance with the presentinvention.

    ______________________________________                                                      weight percent                                                  ______________________________________                                        Urea            32.0   40.0      20.0 0.0                                     Dimethylolurea  0.0    0.0       0.0  20.0                                    Potassium bicarbonate                                                                         36.5   41.0      40.0 0.0                                     Sodium bicarbonate                                                                            0.0    0.0       20.0 54.0                                    Potassium carbonate                                                                           14.0   18.0      0.0  0.0                                     Sodium carbonate                                                                              0.0    0.0       0.0  10.0                                    Dioctyl sodium  17.0   0.0       0.0  0.0                                     sulfosuccinate                                                                Sodium lauryl sulfate                                                                         0.0    0.0       18.0 12.0                                    Magnesium oxide 0.05   1.0       2.0  4.0                                     ______________________________________                                    

Each of the above blended compositions is dispersed in water to providean aqueous formulation having a content of 0.5 weight percent of theurea or dimethylourea ingredient which slow-releases ammonia and/orammonium bicarbonate under the alkaline pH conditions of the aqueousmedium.

Test plots are established in a rice field. Each aqueous formulation isapplied to a test plot at weekly intervals at a rate of 1000 liters perhectare.

After three months, the sprayed plots are healthy, and the untreatedplots are damaged by rice blast fungus (Pericularia oryzae) and producea lower yield of rice.

Under similar test conditions, test plots with formulations notcontaining the urea or dimethylolurea ingredient exhibit a slower growthrate, and minor traces of rice blast fungus are evident.

EXAMPLE II

This Example illustrates the preparation and application of a fungicidecomposition in accordance with the present invention.

A water-dispersible powder composition is prepared from the followingweight percent ingredients:

    ______________________________________                                        urea              50                                                          sodium bicarbonate                                                                              30                                                          potassium carbonate                                                                             15                                                          guar gum           1                                                          diocyl sodium      2                                                          sulfosuccinate                                                                ultrafine silica   2                                                          ______________________________________                                    

The ingredients are blended and jet mill micronized to an averageparticle size of about 20 microns.

Test plots are established in a field planting of cantaloupe, and thecrop is inoculated with powdery mildew fungus (Erysiphe cichoracearum).

The test plots are sprayed with an aqueous dispersion of the powdercomposition. The urea content of the aqueous solution is 0.3 weightpercent.

After a month, the treated plants in the test plots are healthy andgrowing rapidly. The untreated plants are damaged by powdery mildew, andare slow growing.

EXAMPLE III

This Example illustrates the preparation of a fungicide powderformulation for disease prevention in accordance with the presentinvention.

A blend of the following weight percent ingredients is prepared:

    ______________________________________                                        cyanuric acid      20                                                         sodium bicarbonate 30                                                         potassium bicarbonate                                                                            15                                                         sodium stearate    25                                                         xanthan gum        10                                                         ______________________________________                                    

The formulated concentrated powder is diluted with water by thedispersion of 2 parts of the powder blend into 100 parts of water. Theresulting solution is sprayed onto ornamental plant foliage where itforms an adherent coating on the foliage surfaces, and prevents fungaldisease infection of the plants.

EXAMPLE IV

This example illustrates the preparation of a fungicide-fertilizercomposition.

A blend of the following weight ratio of ingredients is prepared:

    ______________________________________                                                       Parts                                                          ______________________________________                                        melamine         20                                                           urea clathrate.sup.(1)                                                                         40                                                           potassium oleate  2                                                           KHCO.sub.3       25                                                           Na.sub.2 CO.sub.3                                                                               5                                                           K.sub.3 PO.sub.4 10                                                           ______________________________________                                         .sup.(1) Urea and occluded dodecanol containing an average of 7 moles of      ethylene oxide.                                                          

Granules are prepared by tumbling the blend, spraying added water toform tacky solids, and then drying the granulated product.

The composition is used in granule form for application to soil, or thecomposition is dispersed in water for spray application to plantfoliage.

.sup.(1) Urea and occluded dodecanol containing an average of 7 moles ofethylene oxide.

What is claimed is:
 1. A fungicide composition consisting of a dry blendformulation adapted for in situ generation of ammonium bicarbonate whichcomprises (1) between about 5-80 weight percent of an ingredientselected from water-soluble organic amides which slow-release ammoniaunder aqueous alkaline pH conditions at ambient temperatures; (2)between about 10-80 weight percent of an ingredient selected from alkalimetal bicarbonates; (3) between about 0-30 weight percent of aningredient selected from alkali metal and ammonium carbonates; and (4)between about 0.5-20 weight percent of a spreader-sticker ingredient;all weights based on the composition weight.
 2. A fungicide compositionin accordance with claim 1 wherein the organic amide is urea or ureaclathrate.
 3. A fungicide composition in accordance with claim 1 whereinthe organic amide is alkali metal carbamate.
 4. A fungicide compositionin accordance with claim 1 wherein the organic amide is biuret ortriuret.
 5. A fungicide composition in accordance with claim 1 whereinthe organic amide is cyanuric acid.
 6. A fungicide composition inaccordance with claim 1 wherein the organic amide is a urea-formaldehydeadduct.
 7. A fungicide composition in accordance with claim 1 whereinthe spreader-sticker ingredient is a cationic, anionic or nonionicsurfactant.
 8. A fungicide composition in accordance with claim 1wherein the spreader-sticker ingredient is an alkali metal or ammoniumsalt of a C₂ -C₂₂ aliphatic-containing carboxylate, sulfonate, sulfateor phosphate.
 9. A fungicide composition in accordance with claim 1wherein the spreader-sticker ingredient is a hydrocolloid gum.
 10. Afungicide composition in accordance with claim 1 wherein thespreader-sticker ingredient is a cellulosic derivative.
 11. A fungicidecomposition in accordance with claim 1 wherein the spreader-stickeringredient is a starch derivative.
 12. A fungicide composition inaccordance with claim 1 wherein the spreader-sticker ingredient is apolyacrylamide derivative.
 13. A fungicide composition in accordancewith claim 1 wherein the spreader-sticker ingredient is a nonphytotoxicaliphatic or triglyceride spray oil.
 14. A fungicide composition inaccordance with claim 1 wherein the ingredients comprise (1) urea; (2)sodium or potassium bicarbonate or a mixture thereof; (3) sodium orpotassium or ammonium carbonate or a mixture thereof; and (4) an alkalimetal or ammonium salt of a C₈ -C₂₂ aliphatic-containing carboxylate,sulfonate, sulfate or phosphate.
 15. An aqueous fungicidal formulationadapted for in situ generation of ammonium bicarbonate under cultivatedplant application conditions, which contains ingredients comprising (1)between about 0.1-5 weight percent of water-soluble organic amide whichslow-releases ammonia under aqueous alkaline pH conditions at ambienttemperature; (2) between about 0.2-5 weight percent of alkali metalbicarbonate; (3) between about 0-2 weight percent of alkali metal orammonium carbonate; and (4) between about 0.02-1.5 percent of aspreader-sticker ingredient; all weights based on the formulationweight.
 16. A fungicide formulation in accordance with claim 15 whereinthe organic amide is urea or urea clathrate.
 17. A fungicide formulationin accordance with claim 15 wherein the spreader-sticker ingredient is acationic, anionic or nonionic surfactant.
 18. A fungicide formulation inaccordance with claim 15 wherein the spreader-sticker ingredient is anonphytotoxic aliphatic or triglyceride spray oil.
 19. A fungicideformulation in accordance with claim 15 wherein the ingredients comprise(1) urea; (2) sodium or potassium bicarbonate or a mixture thereof; (3)sodium or potassium or ammonium carbonate or a mixture thereof; and (4)an alkali metal or ammonium salt of a C₈ -C₂₂ aliphatic-containingcarboxylate, sulfonate, sulfate or phosphate.
 20. A fungicidecomposition in accordance with claim 15 which has an aqueous medium pHbetween about 7.5-10.5.
 21. A method of controlling fungal disease incultivated plants which comprises applying a fungicidally effectiveamount of an aqueous formulation in accordance with claim 15 to theplant foliage to prevent or eradicate fungal infections.
 22. A method inaccordance with claim 21 wherein the aqueous formulation is applied byspraying.